1
|
Khan S, Molloy JE, Puhl H, Schulman H, Vogel SS. Real-time single-molecule imaging of CaMKII-calmodulin interactions. Biophys J 2024; 123:824-838. [PMID: 38414237 DOI: 10.1016/j.bpj.2024.02.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/20/2023] [Accepted: 02/22/2024] [Indexed: 02/29/2024] Open
Abstract
The binding of calcium/calmodulin (CAM) to calcium/calmodulin-dependent protein kinase II (CaMKII) initiates an ATP-driven cascade that triggers CaMKII autophosphorylation. The autophosphorylation in turn increases the CaMKII affinity for CAM. Here, we studied the ATP dependence of CAM association with the actin-binding CaMKIIβ isoform using single-molecule total internal reflection fluorescence microscopy. Rhodamine-CAM associations/dissociations to surface-immobilized Venus-CaMKIIβ were resolved with 0.5 s resolution from video records, batch-processed with a custom algorithm. CAM occupancy was determined simultaneously with spot-photobleaching measurement of CaMKII holoenzyme stoichiometry. We show the ATP-dependent increase of the CAM association requires dimer formation for both the α and β isoforms. The study of mutant β holoenzymes revealed that the ATP-dependent increase in CAM affinity results in two distinct states. The phosphorylation-defective (T287.306-307A) holoenzyme resides only in the low-affinity state. CAM association is further reduced in the T287A holoenzyme relative to T287.306-307A. In the absence of ATP, the affinity of CAM for the T287.306-307A mutant and the wild-type monomer are comparable. The affinity of the ATP-binding impaired (K43R) mutant is even weaker. In ATP, the K43R holoenzyme resides in the low-affinity state. The phosphomimetic mutant (T287D) resides only in a 1000-fold higher-affinity state, with mean CAM occupancy of more than half of the 14-mer holoenzyme stoichiometry in picomolar CAM. ATP promotes T287D holoenzyme disassembly but does not elevate CAM occupancy. Single Poisson distributions characterized the ATP-dependent CAM occupancy of mutant holoenzymes. In contrast, the CAM occupancy of the wild-type population had a two-state distribution with both low- and high-affinity states represented. The low-affinity state was the dominant state, a result different from published in vitro assays. Differences in assay conditions can alter the balance between activating and inhibitory autophosphorylation. Bound ATP could be sufficient for CaMKII structural function, while antagonistic autophosphorylations may tune CaMKII kinase-regulated action-potential frequency decoding in vivo.
Collapse
Affiliation(s)
- Shahid Khan
- Molecular Biology Consortium at Lawrence Berkeley National Laboratory, Berkeley, California.
| | | | - Henry Puhl
- Laboratory of Biophotonics and Quantum Biology, National Institutes on Alcohol, Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Howard Schulman
- Panorama Research Institute, Sunnyvale, California; Stanford University School of Medicine, Stanford, California
| | - Steven S Vogel
- Laboratory of Biophotonics and Quantum Biology, National Institutes on Alcohol, Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| |
Collapse
|
2
|
Li J, He Y, Du YH, Zhang M, Georgi R, Kolberg B, Sun DW, Ma K, Li YF, Zhang XZ. Effect of Electro-acupuncture on Vasomotor Symptoms in Rats with Acute Cerebral Infarction Based on Phosphatidylinositol System. Chin J Integr Med 2021; 28:145-152. [PMID: 34874522 PMCID: PMC8649319 DOI: 10.1007/s11655-021-3341-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2021] [Indexed: 11/29/2022]
Abstract
Objective To investigate the effect of electro-acupuncture (EA) on vasomotor symptoms in rats with acute cerebral infarction, by observing the changes in the expression of factors related to the phosphatidylinositol (PI) system. Methods Forty-two Wistar rats were randomly divided into 3 groups by a random number table: the control group (n=6), the model group (n=18) and the EA group (n=18). The EA group was given EA treatment at Shuigou (GV 26) instantly after modeling with middle cerebral artery occlusion (MCAO) method, while the model and control groups were not given any treatment. The degrees of neurological deficiency were evaluated using neurological severity scores (NSS) and the brain blood flow was evaluated by a laser scanning confocal microscope. Western blot analysis was conducted to detect the expression levels of G-protein subtype (Gq) and calmodulin (CaM). Competition for protein binding was conducted to detect the expression level of inositol triphosphate (IP3). Thin layer quantitative analysis was conducted to detect the expression level of diacylglycerol (DAG). The expression level of intracellular concentration of free calcium ion ([Ca2+]i) was detected by flow cytometry. Results The NSS of the model group was significantly higher than the control group at 3 and 6 h after MCAO (P<0.01), while the EA group was significantly lower than the model group at 6 h (P<0.01). The cerebral blood flow in the model group was significantly lower than the control group at 1, 3 and 6 h after MCAO (P<0.01), while for the EA group it was remarkably higher than the model group at the same time points (P<0.01). The expressions of Gq, CaM, IP3, DAG and [Ca2+]i in the model group were significantly higher than the control group (P<0.05 or P<0.01), and those in the EA group were significantly lower than the model group at the same time points (P<0.05 or P<0.01). Conclusion EA treatment at GV 26 can effectively decrease the over-expression of related factors of PI system in rats with acute cerebral infarction, improve cerebral autonomy movement, and alleviate cerebral vascular spasm.
Collapse
Affiliation(s)
- Jing Li
- Key Laboratory of Acupuncture of Tianjin, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300381, China
| | - Ying He
- Key Laboratory of Acupuncture of Tianjin, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300381, China
| | - Yuan-Hao Du
- Department of Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300381, China.
| | - Min Zhang
- Key Laboratory of Acupuncture of Tianjin, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300381, China
| | - Rainer Georgi
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, 69120, Germany
| | - Bernhard Kolberg
- Department of Internal Medicine, Mannheim Medical School of Heidelberg University, Mannheim, 68167, Germany
| | - Dong-Wei Sun
- Department of Chinese Medicine Rehabilitation, Shenzhen Baoan District Hospital of Traditional Chinese Medicine, Shenzhen, Guangdong Province, 518000, China
| | - Kun Ma
- Department of Preventive Treatment of Disease, Binhai New Area Hospital of Traditional Chinese Medicine, Fourth Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Yong-Feng Li
- Institute of Acupuncture and Moxibustion, Shaanxi University of Chinese Medicine, Xi'an, 712046, China
| | - Xue-Zhu Zhang
- Key Laboratory of Acupuncture of Tianjin, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300381, China
| |
Collapse
|
3
|
Mahling R, Hovey L, Isbell HM, Marx DC, Miller MS, Kilpatrick AM, Weaver LD, Yoder JB, Kim EH, Andresen CNJ, Li S, Shea MA. Na V1.2 EFL domain allosterically enhances Ca 2+ binding to sites I and II of WT and pathogenic calmodulin mutants bound to the channel CTD. Structure 2021; 29:1339-1356.e7. [PMID: 33770503 PMCID: PMC8458505 DOI: 10.1016/j.str.2021.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 12/23/2020] [Accepted: 03/03/2021] [Indexed: 11/23/2022]
Abstract
Neuronal voltage-gated sodium channel NaV1.2 C-terminal domain (CTD) binds calmodulin (CaM) constitutively at its IQ motif. A solution structure (6BUT) and other NMR evidence showed that the CaM N domain (CaMN) is structurally independent of the C-domain (CaMC) whether CaM is bound to the NaV1.2IQp (1,901-1,927) or NaV1.2CTD (1,777-1,937) with or without calcium. However, in the CaM + NaV1.2CTD complex, the Ca2+ affinity of CaMN was more favorable than in free CaM, while Ca2+ affinity for CaMC was weaker than in the CaM + NaV1.2IQp complex. The CTD EF-like (EFL) domain allosterically widened the energetic gap between CaM domains. Cardiomyopathy-associated CaM mutants (N53I(N54I), D95V(D96V), A102V(A103V), E104A(E105A), D129G(D130G), and F141L(F142L)) all bound the NaV1.2 IQ motif favorably under resting (apo) conditions and bound calcium normally at CaMN sites. However, only N53I and A102V bound calcium at CaMC sites at [Ca2+] < 100 μM. Thus, they are expected to respond like wild-type CaM to Ca2+ spikes in excitable cells.
Collapse
Affiliation(s)
- Ryan Mahling
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Liam Hovey
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Holly M Isbell
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Dagan C Marx
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Mark S Miller
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Adina M Kilpatrick
- Department of Physics and Astronomy, Drake University, Des Moines, IA 50311-4516, USA
| | - Lisa D Weaver
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Jesse B Yoder
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Elaine H Kim
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Corinne N J Andresen
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Shuxiang Li
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Madeline A Shea
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA.
| |
Collapse
|
4
|
Mahling R, Rahlf CR, Hansen SC, Hayden MR, Shea MA. Ca 2+-saturated calmodulin binds tightly to the N-terminal domain of A-type fibroblast growth factor homologous factors. J Biol Chem 2021; 296:100458. [PMID: 33639159 PMCID: PMC8059062 DOI: 10.1016/j.jbc.2021.100458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/15/2021] [Accepted: 02/23/2021] [Indexed: 01/12/2023] Open
Abstract
Voltage-gated sodium channels (Navs) are tightly regulated by multiple conserved auxiliary proteins, including the four fibroblast growth factor homologous factors (FGFs), which bind the Nav EF-hand like domain (EFL), and calmodulin (CaM), a multifunctional messenger protein that binds the NaV IQ motif. The EFL domain and IQ motif are contiguous regions of NaV cytosolic C-terminal domains (CTD), placing CaM and FGF in close proximity. However, whether the FGFs and CaM act independently, directly associate, or operate through allosteric interactions to regulate channel function is unknown. Titrations monitored by steady-state fluorescence spectroscopy, structural studies with solution NMR, and computational modeling demonstrated for the first time that both domains of (Ca2+)4-CaM (but not apo CaM) directly bind two sites in the N-terminal domain (NTD) of A-type FGF splice variants (FGF11A, FGF12A, FGF13A, and FGF14A) with high affinity. The weaker of the (Ca2+)4-CaM-binding sites was known via electrophysiology to have a role in long-term inactivation of the channel but not known to bind CaM. FGF12A binding to a complex of CaM associated with a fragment of the NaV1.2 CTD increased the Ca2+-binding affinity of both CaM domains, consistent with (Ca2+)4-CaM interacting preferentially with its higher-affinity site in the FGF12A NTD. Thus, A-type FGFs can compete with NaV IQ motifs for (Ca2+)4-CaM. During spikes in the cytosolic Ca2+ concentration that accompany an action potential, CaM may translocate from the NaV IQ motif to the FGF NTD, or the A-type FGF NTD may recruit a second molecule of CaM to the channel.
Collapse
Affiliation(s)
- Ryan Mahling
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Cade R Rahlf
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Samuel C Hansen
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Matthew R Hayden
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Madeline A Shea
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
| |
Collapse
|
5
|
The Interaction between the Drosophila EAG Potassium Channel and the Protein Kinase CaMKII Involves an Extensive Interface at the Active Site of the Kinase. J Mol Biol 2018; 430:5029-5049. [PMID: 30381148 DOI: 10.1016/j.jmb.2018.10.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 10/23/2018] [Accepted: 10/23/2018] [Indexed: 12/12/2022]
Abstract
The Drosophila EAG (dEAG) potassium channel is the founding member of the superfamily of KNCH channels, which are involved in cardiac repolarization, neuronal excitability and cellular proliferation. In flies, dEAG is involved in regulation of neuron firing and assembles with CaMKII to form a complex implicated in memory formation. We have characterized the interaction between the kinase domain of CaMKII and a 53-residue fragment of the dEAG channel that includes a canonical CaMKII recognition sequence. Crystal structures together with biochemical/biophysical analysis show a substrate-kinase complex with an unusually tight and extensive interface that appears to be strengthened by phosphorylation of the channel fragment. Electrophysiological recordings show that catalytically active CaMKII is required to observe active dEAG channels. A previously identified phosphorylation site in the recognition sequence is not the substrate for this crucial kinase activity, but rather contributes importantly to the tight interaction of the kinase with the channel. The available data suggest that the dEAG channel is a docking platform for the kinase and that phosphorylation of the channel's kinase recognition sequence modulates the strength of the interaction between the channel and the kinase.
Collapse
|
6
|
Vigil FA, Giese KP. Calcium/calmodulin-dependent kinase II and memory destabilization: a new role in memory maintenance. J Neurochem 2018; 147:12-23. [PMID: 29704430 PMCID: PMC6221169 DOI: 10.1111/jnc.14454] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/28/2018] [Accepted: 04/17/2018] [Indexed: 02/03/2023]
Abstract
In this review, we discuss the poorly explored role of calcium/calmodulin-dependent protein kinase II (CaMKII) in memory maintenance, and its influence on memory destabilization. After a brief review on CaMKII and memory destabilization, we present critical pieces of evidence suggesting that CaMKII activity increases retrieval-induced memory destabilization. We then proceed to propose two potential molecular pathways to explain the association between CaMKII activation and increased memory destabilization. This review will pinpoint gaps in our knowledge and discuss some 'controversial' observations, establishing the basis for new experiments on the role of CaMKII in memory reconsolidation. The role of CaMKII in memory destabilization is of great clinical relevance. Still, because of the lack of scientific literature on the subject, more basic science research is necessary to pursue this pathway as a clinical tool.
Collapse
Affiliation(s)
- Fabio Antonio Vigil
- Department of Cell and Integrative PhysiologyThe University of Texas Health San Antonio8403, Floyd Curl DriveSan AntonioTX 78229USA
| | - Karl Peter Giese
- Department of Basic and Clinical NeuroscienceKing's College London125 Coldharbour LaneLondonSE5 9NUUK
| |
Collapse
|
7
|
Nguyen T, Shively JE. Induction of Lumen Formation in a Three-dimensional Model of Mammary Morphogenesis by Transcriptional Regulator ID4: ROLE OF CaMK2D IN THE EPIGENETIC REGULATION OF ID4 GENE EXPRESSION. J Biol Chem 2016; 291:16766-76. [PMID: 27302061 DOI: 10.1074/jbc.m115.710160] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Indexed: 01/19/2023] Open
Abstract
Concomitant loss of lumen formation and cell adhesion protein CEACAM1 is a hallmark feature of breast cancer. In a three-dimensional culture model, transfection of CEACAM1 into MCF7 breast cells can restore lumen formation by an unknown mechanism. ID4, a transcriptional regulator lacking a DNA binding domain, is highly up-regulated in CEACAM1-transfected MCF7 cells, and when down-regulated with RNAi, abrogates lumen formation. Conversely, when MCF7 cells, which fail to form lumena in a three-dimensional culture, are transfected with ID4, lumen formation is restored, demonstrating that ID4 may substitute for CEACAM1. After showing the ID4 promoter is hypermethylated in MCF7 cells but hypomethylated in MCF/CEACAM1 cells, ID4 expression was induced in MCF7 cells by agents affecting chromatin remodeling and methylation. Mechanistically, CaMK2D was up-regulated in CEACAM1-transfected cells, effecting phosphorylation of HDAC4 and its sequestration in the cytoplasm by the adaptor protein 14-3-3. CaMK2D also phosphorylates CEACAM1 on its cytoplasmic domain and mutation of these phosphorylation sites abrogates lumen formation. Thus, CEACAM1 is able to maintain the active transcription of ID4 by an epigenetic mechanism involving HDAC4 and CaMK2D, and the same kinase enables lumen formation by CEACAM1. Because ID4 can replace CEACAM1 in parental MCF7 cells, it must act downstream from CEACAM1 by inhibiting the activity of other transcription factors that would otherwise prevent lumen formation. This overall mechanism may be operative in other cancers, such as colon and prostate, where the down-regulation of CEACAM1 is observed.
Collapse
Affiliation(s)
- Tung Nguyen
- From the Department of Immunology, Beckman Research Institute of City of Hope, Duarte, California 91010
| | - John E Shively
- From the Department of Immunology, Beckman Research Institute of City of Hope, Duarte, California 91010
| |
Collapse
|
8
|
Mattioni M, Le Novère N. Integration of biochemical and electrical signaling-multiscale model of the medium spiny neuron of the striatum. PLoS One 2013; 8:e66811. [PMID: 23843966 PMCID: PMC3700997 DOI: 10.1371/journal.pone.0066811] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 05/14/2013] [Indexed: 01/13/2023] Open
Abstract
Neuron behavior results from the interplay between networks of biochemical processes and electrical signaling. Synaptic plasticity is one of the neuronal properties emerging from such an interaction. One of the current approaches to study plasticity is to model either its electrical aspects or its biochemical components. Among the chief reasons are the different time scales involved, electrical events happening in milliseconds while biochemical cascades respond in minutes or hours. In order to create multiscale models taking in consideration both aspects simultaneously, one needs to synchronize the two models, and exchange relevant variable values. We present a new event-driven algorithm to synchronize different neuronal models, which decreases computational time and avoids superfluous synchronizations. The algorithm is implemented in the TimeScales framework. We demonstrate its use by simulating a new multiscale model of the Medium Spiny Neuron of the Neostriatum. The model comprises over a thousand dendritic spines, where the electrical model interacts with the respective instances of a biochemical model. Our results show that a multiscale model is able to exhibit changes of synaptic plasticity as a result of the interaction between electrical and biochemical signaling. Our synchronization strategy is general enough to be used in simulations of other models with similar synchronization issues, such as networks of neurons. Moreover, the integration between the electrical and the biochemical models opens up the possibility to investigate multiscale process, like synaptic plasticity, in a more global manner, while taking into account a more realistic description of the underlying mechanisms.
Collapse
Affiliation(s)
- Michele Mattioni
- European Molecular Biology Laboratory-The European Bioinformatics Institute (EMBL-EBI), Hinxton, Cambridge, United Kingdom
| | - Nicolas Le Novère
- European Molecular Biology Laboratory-The European Bioinformatics Institute (EMBL-EBI), Hinxton, Cambridge, United Kingdom
- Babraham Institute, Babraham, Cambridge, United Kingdom
- * E-mail:
| |
Collapse
|
9
|
Masada N, Schaks S, Jackson SE, Sinz A, Cooper DMF. Distinct mechanisms of calmodulin binding and regulation of adenylyl cyclases 1 and 8. Biochemistry 2012; 51:7917-29. [PMID: 22971080 PMCID: PMC3466776 DOI: 10.1021/bi300646y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Calmodulin (CaM), by mediating the stimulation of the activity of two adenylyl cyclases (ACs), plays a key role in integrating the cAMP and Ca(2+) signaling systems. These ACs, AC1 and AC8, by decoding discrete Ca(2+) signals can contribute to fine-tuning intracellular cAMP dynamics, particularly in neurons where they predominate. CaM comprises an α-helical linker separating two globular regions at the N-terminus and the C-terminus that each bind two Ca(2+) ions. These two lobes have differing affinities for Ca(2+), and they can interact with target proteins independently. This study explores previous indications that the two lobes of CaM can regulate AC1 and AC8 differently and thereby yield different responses to cellular transitions in [Ca(2+)](i). We first compared by glutathione S-transferase pull-down assays and offline nanoelectrospray ionization mass spectrometry the interaction of CaM and Ca(2+)-binding deficient mutants of CaM with the internal CaM binding domain (CaMBD) of AC1 and the two terminal CaMBDs of AC8. We then examined the influence of these three CaMBDs on Ca(2+) binding by native and mutated CaM in stopped-flow experiments to quantify their interactions. The three CaMBDs show quite distinct interactions with the two lobes of CaM. These findings establish the critical kinetic differences between the mechanisms of Ca(2+)-CaM activation of AC1 and AC8, which may underpin their different physiological roles.
Collapse
Affiliation(s)
- Nanako Masada
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | | | | | | | | |
Collapse
|
10
|
Li L, Stefan MI, Le Novère N. Calcium input frequency, duration and amplitude differentially modulate the relative activation of calcineurin and CaMKII. PLoS One 2012; 7:e43810. [PMID: 22962589 PMCID: PMC3433481 DOI: 10.1371/journal.pone.0043810] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 07/26/2012] [Indexed: 11/18/2022] Open
Abstract
NMDA receptor dependent long-term potentiation (LTP) and long-term depression (LTD) are two prominent forms of synaptic plasticity, both of which are triggered by post-synaptic calcium elevation. To understand how calcium selectively stimulates two opposing processes, we developed a detailed computational model and performed simulations with different calcium input frequencies, amplitudes, and durations. We show that with a total amount of calcium ions kept constant, high frequencies of calcium pulses stimulate calmodulin more efficiently. Calcium input activates both calcineurin and Ca2+/calmodulin-dependent protein kinase II (CaMKII) at all frequencies, but increased frequencies shift the relative activation from calcineurin to CaMKII. Irrespective of amplitude and duration of the inputs, the total amount of calcium ions injected adjusts the sensitivity of the system to calcium input frequencies. At a given frequency, the quantity of CaMKII activated is proportional to the total amount of calcium. Thus, an input of a small amount of calcium at high frequencies can induce the same activation of CaMKII as a larger amount, at lower frequencies. Finally, the extent of activation of CaMKII signals with high calcium frequency is further controlled by other factors, including the availability of calmodulin, and by the potency of phosphatase inhibitors.
Collapse
Affiliation(s)
| | | | - Nicolas Le Novère
- EMBL European Bioinformatics Institute, Hinxton, United Kingdom
- * E-mail:
| |
Collapse
|
11
|
Jama AM, Gabriel J, Al-Nagar AJ, Martin S, Baig SZ, Soleymani H, Chowdhury Z, Beesley P, Török K. Lobe-specific functions of Ca2+·calmodulin in alphaCa2+·calmodulin-dependent protein kinase II activation. J Biol Chem 2011; 286:12308-16. [PMID: 21300804 PMCID: PMC3069434 DOI: 10.1074/jbc.m110.157057] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
N-Methyl-d-aspartic acid receptor-dependent long term potentiation (LTP), a model of memory formation, requires Ca2+·calmodulin-dependent protein kinase II (αCaMKII) activity and Thr286 autophosphorylation via both global and local Ca2+ signaling, but the mechanisms of signal transduction are not understood. We tested the hypothesis that the Ca2+-binding activator protein calmodulin (CaM) is the primary decoder of Ca2+ signals, thereby determining the output, e.g. LTP. Thus, we investigated the function of CaM mutants, deficient in Ca2+ binding at sites 1 and 2 of the N-terminal lobe or sites 3 and 4 of the C-terminal CaM lobe, in the activation of αCaMKII. Occupancy of CaM Ca2+ binding sites 1, 3, and 4 is necessary and sufficient for full activation. Moreover, the N- and C-terminal CaM lobes have distinct functions. Ca2+ binding to N lobe Ca2+ binding site 1 increases the turnover rate of the enzyme 5-fold, whereas the C lobe plays a dual role; it is required for full activity, but in addition, via Ca2+ binding site 3, it stabilizes ATP binding to αCaMKII 4-fold. Thr286 autophosphorylation is also dependent on Ca2+ binding sites on both the N and the C lobes of CaM. As the CaM C lobe sites are populated by low amplitude/low frequency (global) Ca2+ signals, but occupancy of N lobe site 1 and thus activation of αCaMKII requires high amplitude/high frequency (local) Ca2+ signals, lobe-specific sensing of Ca2+-signaling patterns by CaM is proposed to explain the requirement for both global and local Ca2+ signaling in the induction of LTP via αCaMKII.
Collapse
Affiliation(s)
- Abdirahman M Jama
- Division of Basic Medical Sciences, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Jama AM, Fenton J, Robertson SD, Török K. Time-dependent autoinactivation of phospho-Thr286-alphaCa2+/calmodulin-dependent protein kinase II. J Biol Chem 2009; 284:28146-28155. [PMID: 19654320 PMCID: PMC2788865 DOI: 10.1074/jbc.m109.005900] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (αCaMKII) is thought to exert its role in memory formation by autonomous Ca2+-independent persistent activity conferred by Thr286 autophosphorylation, allowing the enzyme to remain active even when intracellular [Ca2+] has returned to resting levels. Ca2+ sequestration-induced inhibition, caused by a burst of Thr305/306 autophosphorylation via calmodulin (CaM) dissociation from the Thr305/306 sites, is in conflict with this view. The processes of CaM binding, autophosphorylation, and inactivation are dissected to resolve this conflict. Upon Ca2+ withdrawal, CaM sequential domain dissociation is observed, starting with the rapid release of the first (presumed N-terminal) CaM lobe, thought to be bound at the Thr305/306 sites. The time courses of Thr305/306 autophosphorylation and inactivation, however, correlate with the slow dissociation of the second (presumed C-terminal) CaM lobe. Exposure of the Thr305/306 sites is thus not sufficient for their autophosphorylation. Moreover, Thr305/306 autophosphorylation and autoinactivation are shown to occur in the continuous presence of Ca2+ and bound Ca2+/CaM by time courses similar to those seen following Ca2+ sequestration. Our investigation of the activity and mechanisms of phospho-Thr286-αCaMKII thus shows time-dependent autoinactivation, irrespective of the continued presence of Ca2+ and CaM, allowing a very short, if any, time window for Ca2+/CaM-free phospho-Thr286-αCaMKII activity. Physiologically, the time-dependent autoinactivation mechanisms of phospho-Thr286-αCaMKII (t½ of ∼50 s at 37 °C) suggest a transient kinase activity of ∼1 min duration in the induction of long term potentiation and thus memory formation.
Collapse
Affiliation(s)
- Abdirahman M Jama
- Division of Basic Medical Sciences, St George's, University of London, Cranmer Terrace, London SW17 0RE, United Kingdom
| | - Jon Fenton
- Division of Basic Medical Sciences, St George's, University of London, Cranmer Terrace, London SW17 0RE, United Kingdom
| | - Saralili D Robertson
- Division of Basic Medical Sciences, St George's, University of London, Cranmer Terrace, London SW17 0RE, United Kingdom
| | - Katalin Török
- Division of Basic Medical Sciences, St George's, University of London, Cranmer Terrace, London SW17 0RE, United Kingdom.
| |
Collapse
|
13
|
Raveendran R, Devi Suma Priya S, Mayadevi M, Steephan M, Santhoshkumar TR, Cheriyan J, Sanalkumar R, Pradeep KK, James J, Omkumar RV. Phosphorylation status of the NR2B subunit of NMDA receptor regulates its interaction with calcium/calmodulin-dependent protein kinase II. J Neurochem 2009; 110:92-105. [DOI: 10.1111/j.1471-4159.2009.06108.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
14
|
A two-state model for Ca2+/CaM-dependent protein kinase II (αCaMKII) in response to persistent Ca2+ stimulation in hippocampal neurons. Cell Calcium 2008; 44:465-78. [DOI: 10.1016/j.ceca.2008.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 02/01/2008] [Accepted: 03/05/2008] [Indexed: 11/24/2022]
|
15
|
Dodd R, Peracchia C, Stolady D, Török K. Calmodulin association with connexin32-derived peptides suggests trans-domain interaction in chemical gating of gap junction channels. J Biol Chem 2008; 283:26911-20. [PMID: 18676375 PMCID: PMC2555998 DOI: 10.1074/jbc.m801434200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 07/14/2008] [Indexed: 12/30/2022] Open
Abstract
Calmodulin plays a key role in the chemical gating of gap junction channels. Two calmodulin-binding regions have previously been identified in connexin32 gap junction protein, one in the N-terminal and another in the C-terminal cytoplasmic tail of the molecule. The aim of this study was to better understand how calmodulin interacts with the connexin32-binding domains. Lobe-specific interactions of calmodulin with connexin32 peptides were studied by stopped flow kinetics, using Ca(2+) binding-deficient mutants. Peptides corresponding to the N-terminal tail (residues 1-22) of connexin32 engaged both the N- and C-terminal lobes (N- and C-lobes) of calmodulin, binding with higher affinity to the C-lobe of calmodulin (Ca(2+) dissociation rate constants k(3,4), 1.7+/-0.5 s(-1)) than to the N-lobe (k(1,2), 10.8+/-1.3 s(-1)). In contrast, peptides representing the C-terminal tail domain (residues 208-227) of connexin32 bound either the C- or the N-lobe but only one calmodulin lobe at a time (k(3,4), 2.6+/-0.1 s(-1) or k(1), 13.8+/-0.5 s(-1) and k(2), 1000 s(-1)). The calmodulin-binding domains of the N- and C-terminal tails of connexin32 were best defined as residues 1-21 and 216-227, respectively. Our data, showing separate functions of the N- and C-lobes of calmodulin in the interactions with connexin32, suggest trans-domain or trans-subunit bridging by calmodulin as a possible mechanism of gap junction gating.
Collapse
Affiliation(s)
- Ryan Dodd
- Division of Basic Medical Sciences, St George's, University of London, London, SW17 0RE United Kingdom
| | | | | | | |
Collapse
|
16
|
Forest A, Swulius MT, Tse JKY, Bradshaw JM, Gaertner T, Waxham MN. Role of the N- and C-lobes of calmodulin in the activation of Ca(2+)/calmodulin-dependent protein kinase II. Biochemistry 2008; 47:10587-99. [PMID: 18795794 DOI: 10.1021/bi8007033] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding the principles of calmodulin (CaM) activation of target enzymes will help delineate how this seemingly simple molecule can play such a complex role in transducing Ca (2+)-signals to a variety of downstream pathways. In the work reported here, we use biochemical and biophysical tools and a panel of CaM constructs to examine the lobe specific interactions between CaM and CaMKII necessary for the activation and autophosphorylation of the enzyme. Interestingly, the N-terminal lobe of CaM by itself was able to partially activate and allow autophosphorylation of CaMKII while the C-terminal lobe was inactive. When used together, CaMN and CaMC produced maximal CaMKII activation and autophosphorylation. Moreover, CaMNN and CaMCC (chimeras of the two N- or C-terminal lobes) both activated the kinase but with greater K act than for wtCaM. Isothermal titration calorimetry experiments showed the same rank order of affinities of wtCaM > CaMNN > CaMCC as those determined in the activity assay and that the CaM to CaMKII subunit binding ratio was 1:1. Together, our results lead to a proposed sequential mechanism to describe the activation pathway of CaMKII led by binding of the N-lobe followed by the C-lobe. This mechanism contrasts the typical sequential binding mode of CaM with other CaM-dependent enzymes, where the C-lobe of CaM binds first. The consequence of such lobe specific binding mechanisms is discussed in relation to the differential rates of Ca (2+)-binding to each lobe of CaM during intracellular Ca (2+) oscillations.
Collapse
Affiliation(s)
- Amelie Forest
- The Department of Neurobiology and Anatomy, the University of Texas Medical School at Houston, Houston, Texas 77030, USA
| | | | | | | | | | | |
Collapse
|
17
|
El-Mlili N, Rodrigo R, Naghizadeh B, Cauli O, Felipo V. Chronic hyperammonemia reduces the activity of neuronal nitric oxide synthase in cerebellum by altering its localization and increasing its phosphorylation by calcium-calmodulin kinase II. J Neurochem 2008; 106:1440-9. [PMID: 18498443 DOI: 10.1111/j.1471-4159.2008.05495.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Impaired function of the glutamate-nitric oxide-cGMP pathway contributes to cognitive impairment in hyperammonemia and hepatic encephalopathy. The mechanisms by which hyperammonemia impairs this pathway remain unclear. Understanding these mechanisms would allow designing clinical treatments for cognitive deficits in hepatic encephalopathy. The aims of this work were: (i) to assess whether chronic hyperammonemia in vivo alters basal activity of neuronal nitric oxide synthase (nNOS) in cerebellum and/or its activation in response to NMDA receptor activation and (ii) to analyse the molecular mechanisms by which hyperammonemia induces these alterations. It is shown that hyperammonemia reduces both basal activity of nNOS and its activation following NMDA receptor activation. Reduced basal activity is because of increased phosphorylation in Ser847 (by 69%) which reduces basal activity of nNOS by about 40%. Increased phosphorylation of nNOS in Ser847 is because of increased activity of calcium-calmodulin-dependent protein kinases (CaMKII) which in turn is because of increased phosphorylation at Thr286. Inhibiting CaMKII with KN-62 normalizes phosphorylation of Ser847 and basal NOS activity in hyperammonemic rats, returning to values similar to controls. Reduced activation of nNOS in response to NMDA receptor activation in hyperammonemia is because of altered subcellular localization of nNOS, with reduced amount in post-synaptic membranes and increased amount in the cytosol.
Collapse
Affiliation(s)
- Nisrin El-Mlili
- Laboratory of Neurobiology, Centro de Investigacion Principe Felipe, Valencia, Spain
| | | | | | | | | |
Collapse
|
18
|
Calcium Signaling Pathways. Biophys J 2008. [DOI: 10.1016/s0006-3495(08)79015-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
19
|
Thorogate R, Török K. Role of Ca2+ activation and bilobal structure of calmodulin in nuclear and nucleolar localization. Biochem J 2007; 402:71-80. [PMID: 17040208 PMCID: PMC1783980 DOI: 10.1042/bj20061111] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ca2+ signalling to the nucleus is thought to occur by calmodulin entry into the nucleus where calmodulin has many functions. In the present study we have investigated the role of Ca2+ and the N- and C-terminal lobes of calmodulin in its subnuclear targeting by using fluorescently labelled calmodulin and its mutants and confocal microscopy. Our data show, first, that Ca2+ stimulation induces a reorganization of subnuclear structures to which apo-calmodulin can bind. Secondly, Ca2+-independent association of the C-terminal lobe is seen with subnuclear structures such as chromatin, the nuclear envelope and the nucleoli. Thirdly, Ca2+-dependent accumulation of both calmodulin and the C-terminal calmodulin lobe occurs in the nucleoli. The N-terminal lobe of calmodulin does not show significant binding to subnuclear structures although, similarly to the C-terminal lobe, it accumulates in the nucleoplasm of wheat germ agglutinin-blocked nuclei suggesting that a facilitated nuclear export mechanism exists for calmodulin.
Collapse
Affiliation(s)
- Richard Thorogate
- Division of Basic Medical Sciences, St George's University of London, London SW17 0RE, UK
| | | |
Collapse
|
20
|
Thorogate R, Török K. Ca2+-dependent and -independent mechanisms of calmodulin nuclear translocation. J Cell Sci 2004; 117:5923-36. [PMID: 15522886 DOI: 10.1242/jcs.01510] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Translocation from the cytosol to the nucleus is a major response by calmodulin (CaM) to stimulation of cells by Ca2+. However, the mechanisms involved in this process are still controversial and both passive and facilitated diffusion have been put forward. We tested nuclear translocation mechanisms in electroporated HeLa cells, rat cortical neurons and glial cells using novel calmodulin and inhibitor peptide probes and confocal microscopy. Passive diffusion of calmodulin across the nuclear membrane was measured in conditions in which facilitated transport was blocked and was compared to that of a similarly sized fluorescein-labeled dextran. Wheat germ agglutinin, which blocks facilitated transport but not passive diffusion, inhibited the nuclear entry of both wild-type and Ca2+-binding-deficient mutant calmodulin both in low and elevated [Ca2+]. Ca2+-dependent nuclear translocation was prevented by a membrane-permeant CaM inhibitor, the mTrp peptide, which indicated that it was specific to Ca2+/CaM. Diffusion of free CaM and Ca2+/CaM was considerably slower than the observed nuclear translocation by facilitated transport. Our data show that the majority of CaM nuclear entry occurred by facilitated mechanisms in all cell types examined, in part by a Ca2+-independent and in part by a Ca2+-dependent translocation mechanism.
Collapse
Affiliation(s)
- Richard Thorogate
- Department of Basic Medical Sciences, St Georges Hospital Medical School, Cranmer Terrace, London, SW17 0RE, UK
| | | |
Collapse
|